My right toolbar is gone
In this case Ctrl + Uparrow is what you need. Or the "return to previous" button up the top.
You've entered the 'maximized' view mode which makes one panel (in this case the 3D view) occupy the whole screen.

Another very useful trick is to create a new file (File -> New) and then open your file with out loading the UI. To open a file without loading the UI, go File -> Open and then select your file, and uncheck the 'Load UI' button on the lower left before opening it,